1. Field of the Invention
The present invention relates generally to an air conditioner for use in an automotive vehicle, and more particularly to an air conditioner having a rear duct for introducing appropriately regulated air to a rear portion of a passenger compartment.
2. Description of the Prior Art
Japanese Patent Laid-open Application (unexamined) No. 60-139518 discloses an air conditioner, suited for use in an automotive vehicle, for introducing appropriately regulated air from the front side to a passenger compartment. The air conditioner is provided with a rear duct branched and extending rearwardly from an air chamber formed downstream of a blower so that appropriately regulated air may be fed to rear seats through the rear duct.
In an automotive vehicle, air from an air conditioner is generally initially fed to front seats and then to rear seats. However, the provision of a rear duct enables appropriately regulated air to be positively fed to the rear seats. By way of example, the rear duct is branched from an air chamber formed between a cooling unit and a heating unit. When a passenger compartment reaches a stable warm condition during a heating operation of the air conditioner, appropriately regulated air having a relatively low temperature is directed to the head or the upper part of the body of a rear seat occupant through the rear duct to make him cool, thereby enhancing the comfortability of his sitting on the rear seats.
This kind of air conditioner is generally provided with an opening and closing means, for example a damper, for opening and closing the rear duct or a rear blower dedicated for use by a rear seat occupant. Manipulation of such means with the use of a manual switch i.e., a rear air conditioner switch controls air to be introduced to the rear seats according to the will of the rear seat occupant.
However, when the rear seat occupant gets off the automotive vehicle, he occasionally forgets turning off the manual switch. In this case, OFF-operation of an ignition switch followed by the stop in operation of the air conditioner terminates the introduction of air to the rear. Thereafter, when the ignition switch is turned on to start the automotive vehicle, the manual switch is also turned on at the same time.
Because of this, when the ignition switch is turned on under the conditions in which the temperature of external air is very low, for example, in winter, cold air is suddenly introduced to the rear through the rear duct, thus making the rear seat occupant uncomfortable.